transactions and dblink

I have 2 dbs, let's call them writedb and readdb. Readdb has a dblink to writedb and a view to a table over that dblink.

I do an update on writedb to that table which view points to and then read from that table over the dblink. I appear to be seeing old values for seconds after the transaction commits even if I set isolation level to SERIALIZABLE.

Does this make any sense?